5th INTERNATIONAL WORKSHOP ON ELECTRODEPOSITED NANOSTRUCTURES 7-9 June 2007, Iasi, Romania	ABSTRACTS

Mechanical characteristic and preparation of gold-carbon nanotube composite P. Cojocaru, A. Vicenzo, P.L. Cavallotti Dipartimento di Chimica, Materiali, Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, 20131 Milano, Italy E-mail: paula.cojocaru@polimi.it Metal matrix composite prepared by either electrochemical or autocatalytic deposition find their leading applications, and so far probably unique as long as current industrial practice is concerned, as wear resistant or self-lubricating coatings [1]. The potential of electrocodeposition for other applications is still scarcely explored, probably also because of the peculiar intricacy of the deposition process. Process design and definition must consider different and dissimilar factors and facing specific problems: the properties of the particles, the bath composition and operating conditions; the lack of one-way correlation between operating parameters and coatings properties, which depends on both the volume fraction of the dispersed phase and the size and distribution of particles [2,3]. Recent work on CNT/metal matrix composite by ECD shows that wear behavior can be significantly improved thanks to self-lubricating property of the composite layer. In the present work we described the results of electrodeposition of gold matrix composite coatings with carbon nanotube CNT. The multiwalled CNTs used in the present study were obtained by a CVD process on iron catalyst supported on alumina by catalytic decomposition of acetylene. The diameter of CNTs was in the range of 20-40 nm, the length ranged from a few to several tenths micrometers. The effects of the bath load on some representative properties of the composite are specifically addressed. Experiments were performed using a sulphite gold electroplating bath a pH 7.5 and from 0.1 to 5 g/l (CNT load). The codeposition was characterized in terms of carbon content of the coating and by examination of the composite coating morphology. The influence of codeposited material on microindentation hardness, wear behavior and thermal stability was investigated. A slight decrease of microhradness was observed for gold composite with increasing C%. Wear performance of Au\CNT composite coatings is significantly improved as compared to the Au matrix, even at very low level of codeposition, resulting in carbon content in the range 0.05 to 0.1%. The thermal stability showed a slight improvement in the case of CNT codeposition, even at carbon content below 0.1%. References [1] C. Buelens, J.P. Celis and J.R. Ross, J. Appl. Electrochem. 13 (1983) 541. [2] Hovestad, L.J.J. Janssen, J. Appl. Electrochem. 40 (1995) 519. [3] J.L. Stojak, J. Fransaer, J.B. Talbot, in "Advances in Electrochemical Science and Engineering", R.C. Alkire and D.M. Kolb Eds., Vol. 7, Wiley VCH, Weinheim, Germany (2002); pp. 193.

 
 
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